From ea157401996931081850818cef07a9e6d2c75e61 Mon Sep 17 00:00:00 2001
From: Robert Craigie <robert@craigie.dev>
Date: Sat, 24 Feb 2024 19:46:54 +0000
Subject: [PATCH] chore(internal): add change case util functions

Co-Authored-By: lxxonx <leeonechang92@gmail.com>
---
 src/prisma/generator/utils.py       | 46 ++++++++++++++++++++++
 tests/test_generation/test_utils.py | 61 ++++++++++++++++++++++++++++-
 2 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/src/prisma/generator/utils.py b/src/prisma/generator/utils.py
index c7eca3443..dadc8dc14 100644
--- a/src/prisma/generator/utils.py
+++ b/src/prisma/generator/utils.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 import os
+import re
 import shutil
 from typing import TYPE_CHECKING, Any, Dict, List, Union, TypeVar, Iterator
 from pathlib import Path
@@ -122,3 +125,46 @@ def clean_multiline(string: str) -> str:
     assert string, 'Expected non-empty string'
     lines = string.splitlines()
     return '\n'.join([dedent(lines[0]), *lines[1:]])
+
+
+# https://github.com/nficano/humps/blob/master/humps/main.py
+
+ACRONYM_RE = re.compile(r'([A-Z\d]+)(?=[A-Z\d]|$)')
+PASCAL_RE = re.compile(r'([^\-_]+)')
+SPLIT_RE = re.compile(r'([\-_]*[A-Z][^A-Z]*[\-_]*)')
+UNDERSCORE_RE = re.compile(r'(?<=[^\-_])[\-_]+[^\-_]')
+
+
+def to_snake_case(input_str: str) -> str:
+    if to_camel_case(input_str) == input_str or to_pascal_case(input_str) == input_str:  # if camel case or pascal case
+        input_str = ACRONYM_RE.sub(lambda m: m.group(0).title(), input_str)
+        input_str = '_'.join(s for s in SPLIT_RE.split(input_str) if s)
+        return input_str.lower()
+    else:
+        input_str = re.sub(r'[^a-zA-Z0-9]', '_', input_str)
+        input_str = input_str.lower().strip('_')
+
+        return input_str
+
+
+def to_camel_case(input_str: str) -> str:
+    if len(input_str) != 0 and not input_str[:2].isupper():
+        input_str = input_str[0].lower() + input_str[1:]
+    return UNDERSCORE_RE.sub(lambda m: m.group(0)[-1].upper(), input_str)
+
+
+def to_pascal_case(input_str: str) -> str:
+    def _replace_fn(match: re.Match[str]) -> str:
+        return match.group(1)[0].upper() + match.group(1)[1:]
+
+    input_str = to_camel_case(PASCAL_RE.sub(_replace_fn, input_str))
+    return input_str[0].upper() + input_str[1:] if len(input_str) != 0 else input_str
+
+
+def to_constant_case(input_str: str) -> str:
+    """Converts to snake case + uppercase, examples:
+
+    foo_bar -> FOO_BAR
+    fooBar -> FOO_BAR
+    """
+    return to_snake_case(input_str).upper()
diff --git a/tests/test_generation/test_utils.py b/tests/test_generation/test_utils.py
index a77569cb4..207954ef8 100644
--- a/tests/test_generation/test_utils.py
+++ b/tests/test_generation/test_utils.py
@@ -1,4 +1,11 @@
-from prisma.generator.utils import copy_tree
+import pytest
+from prisma.generator.utils import (
+    copy_tree,
+    to_camel_case,
+    to_constant_case,
+    to_snake_case,
+    to_pascal_case,
+)
 
 from ..utils import Testdir
 
@@ -26,3 +33,55 @@ def test_copy_tree_ignores_files(testdir: Testdir) -> None:
     assert files[0].name == 'bar.py'
     assert files[1].name == 'foo.py'
     assert files[2].name == 'hello.py'
+
+
+@pytest.mark.parametrize(
+    'input_str,expected',
+    [
+        ('snake_case_test', 'snake_case_test'),
+        ('PascalCaseTest', 'pascal_case_test'),
+        ('camelCaseTest', 'camel_case_test'),
+        ('Mixed_Case_Test', 'mixed_case_test'),
+    ],
+)
+def test_to_snake_case(input_str: str, expected: str) -> None:
+    assert to_snake_case(input_str) == expected
+
+
+@pytest.mark.parametrize(
+    'input_str,expected',
+    [
+        ('snake_case_test', 'SnakeCaseTest'),
+        ('PascalCaseTest', 'PascalCaseTest'),
+        ('camelCaseTest', 'CamelCaseTest'),
+        ('Mixed_Case_Test', 'MixedCaseTest'),
+    ],
+)
+def test_to_pascal_case(input_str: str, expected: str) -> None:
+    assert to_pascal_case(input_str) == expected
+
+
+@pytest.mark.parametrize(
+    'input_str,expected',
+    [
+        ('snake_case_test', 'snakeCaseTest'),
+        ('PascalCaseTest', 'pascalCaseTest'),
+        ('camelCaseTest', 'camelCaseTest'),
+        ('Mixed_Case_Test', 'mixedCaseTest'),
+    ],
+)
+def test_to_camel_case(input_str: str, expected: str) -> None:
+    assert to_camel_case(input_str) == expected
+
+
+@pytest.mark.parametrize(
+    'input_str,expected',
+    [
+        ('snake_case_test', 'SNAKE_CASE_TEST'),
+        ('PascalCaseTest', 'PASCAL_CASE_TEST'),
+        ('camelCaseTest', 'CAMEL_CASE_TEST'),
+        ('Mixed_Case_Test', 'MIXED_CASE_TEST'),
+    ],
+)
+def test_to_constant_case(input_str: str, expected: str) -> None:
+    assert to_constant_case(input_str) == expected